Yes I love Perth, my wife is from there and it is where we met. It was always the long term plan - we also both have family in Perth.
I like the hills, but want to be closer to the city - my wife grew up in Applecross, so we will probably try around there for Applecross High School zone.

Boom! The move to Perth is back on: Work have just pulled out of moving us to Sydney early next year, so we will be waiting until the house is sold and taking my wife back home!
We have visited on and off but are conscious Perth is a lot busier than it was when we left 15 years ago. My wife grew up in Applecross and surrounds, and we lived there for 6 months before we left, plus family in Como, Vic park areas, so we will be looking to stay around that area. Hopefully a dip in house prices offsets the drop in the pound...

Unfortunately if you mean the flag in the system saying medical required that is not the same as an email from a case officer asking you to submit your medical.
There is no reason to delay uploading your form 80.

It will certainly help to be living together with mutual financial commitments:
Lease in both names
Joint bank account payment going in and joint commitments being paid out of it
Bills in both names + other individual correspondence to the same address
Both names on car insurance
Evidence of travel together - joint names on booking documentation
As Ali mentioned, Dating is not a defacto relationship, but you can overcome the 1 year requirement by registering, so I would focus on moving quickly into that status now.